pub fn runtime_fallback(tmp: &Path, home: Option<&Path>, uid: u32) -> PathBufExpand description
The runtime directory when XDG_RUNTIME_DIR is unset: ljos-UID under
the temporary directory, so two users on one host never read each
other’s holds, seat records or approvals. A ljos-UID that is a
symlink, or that another user made first, is not used; the seat then
keeps its records under ~/.cache/ljos/run.